This invention relates to a process for separating a fluid component from a fluid mixture containing the fluid component using microchannel process technology. This invention is particularly suitable for separating purified oxygen from sources such as air containing the oxygen.
When oxygen is used as a raw material source for processes such as combustion, welding and cutting, the operation of fuel cells or in chemical manufacturing, the performance and economics of such processes, and the environmental compatibility of the exhaust gases produced by such processes typically improve as the purity of O2 in the feed gas increases.
Air is a primary source for O2. However, air contains 21% O2, leaving 79% of the air (mostly N2) to pass through the processes employing oxygen as a raw material source thereby degrading the performance of such process without adding value. For example, the N2 component in air may consume pressurization energy, provide N for NOx formation, cool flame temperatures, dilute the product gases, and require larger and more costly gas handling equipment.
Cryogenic distillation is a commonly used technique for purifying O2. However, this process requires large scale operations to achieve economies of scale in order to produce high purity O2. Another is pressure swing adsorption (PSA). With PSA, O2 is forced under pressure to penetrate into molecular-size pores in sorbent materials (normally zeolites), where it does so only slightly further than N2 in the same diffusion time. Then on pressure release, the N2 is removed slightly faster than the O2 which is sorbed a little more strongly by the pores. By adding many stages with cross-flow and counter-flow design, purification of O2 may be achieved. However, for both techniques, the cost and complexity of pressurization throughout the process is significant. A third technique involves electrolysis of aqueous KOH solution, where H2 gas is also produced. The cost of electricity for this technique is high and as a result the technique is seldom used. Due to the wide number of uses for purified O2 and the scales of use of this material, the foregoing techniques for purifying oxygen are insufficient. The problem, therefore, is to provide a more efficient technique for purifying oxygen.
The present invention provides a solution to this problem by providing an efficient process for purifying oxygen. The inventive process is also suitable for effecting other fluid separations.
This invention relates to a process for separating a fluid component from a fluid mixture comprising the fluid component, the process comprising:
(A) flowing the fluid mixture into a microchannel separator; the microchannel separator comprising a plurality of process microchannels containing a sorption medium, a header providing a flow passageway for fluid to enter the process microchannels, and a footer providing a flow passageway for fluid to leave the process microchannels, the combined internal volume of the header and the footer being up to about 40% of the internal volume of the process microchannels; the fluid mixture being maintained in the microchannel separator until at least part of the fluid component is sorbed by the sorption medium; purging the microchannel separator to displace non-sorbed parts of the fluid mixture from the microchannel separator; and
(B) desorbing the fluid component from the sorption medium and flowing a flush fluid through the microchannel separator to displace the desorbed fluid component from the microchannel separator.
In one embodiment, the invention relates to a process for separating a fluid component from a fluid mixture comprising the fluid component, the process comprising:
(I)(A) flowing part of the fluid mixture into a first microchannel separator; the first microchannel separator comprising a plurality of first process microchannels containing a first sorption medium, a first header providing a flow passageway for fluid to enter the first process microchannels, and a first footer providing a flow passageway for fluid to leave the first process microchannels, the combined internal volume of the first header and the first footer being up to about 40% of the internal volume of the first process microchannels; the fluid mixture being maintained in the first microchannel separator until at least part of the fluid component is sorbed by the first sorption medium; purging the first microchannel separator to displace non-sorbed parts of the fluid mixture from the first microchannel separator;
(I)(B) desorbing the fluid component from the first sorption medium and flowing a first flush fluid through the first microchannel separator to displace the desorbed fluid component from the first microchannel separator;
(II)(A) flowing another part of the fluid mixture into a second microchannel separator; the second microchannel separator comprising a plurality of second process microchannels containing a second sorption medium, a second header providing a flow passageway for fluid to enter the second process microchannels, and a second footer providing a flow passageway for fluid to leave the second process microchannels, the combined internal volume of the second header and the second footer being up to about 40% of the internal volume of the second process microchannels; the fluid mixture being maintained in the second microchannel separator until at least part of the fluid component is sorbed by the second sorption medium; purging the second microchannel separator to displace non-sorbed parts of the fluid mixture from the second microchannel separator; and
(II)(B) desorbing the fluid component from the second sorption medium and flowing a second flush fluid through the second microchannel separator to displace the desorbed fluid component from the second microchannel separator.
In one embodiment, the invention relates to a process for separating a first fluid component from a second fluid component, the first fluid component and the second fluid component being contained in a first fluid mixture, the process comprising:
(I) mixing the first fluid mixture with a third fluid component to form a second fluid mixture;
(II) separating the second fluid mixture into a third fluid mixture and a fourth fluid mixture, the third fluid mixture comprising the first fluid component and the third fluid component, the fourth fluid mixture comprising the second fluid component and the third fluid component:
(III)(A) flowing the third fluid mixture into a first microchannel separator; the first microchannel separator comprising a plurality of first process microchannels containing a first sorption medium, a first header providing a flow passageway for fluid to enter the first process microchannels, and a first footer providing a flow passageway for fluid to leave the first process microchannels, the combined internal volume of the first header and the first footer being up to about 40% of the internal volume of the first process microchannels; the third fluid mixture being maintained in the first microchannel separator until at least part of the first fluid component is sorbed by the first sorption medium; purging the first microchannel separator to displace non-sorbed parts of the third fluid mixture from the first microchannel separator;
(III)(B) desorbing the first fluid component from the first sorption medium and flowing a first flush fluid through the first microchannel separator to displace the desorbed first fluid component from the first microchannel separator;
(IV)(A) flowing the fourth fluid mixture into a second microchannel separator; the second microchannel separator comprising a plurality of second process microchannels containing a second sorption medium, a second header providing a flow passageway for fluid to enter the second process microchannels, and a second footer providing a flow passageway for fluid to leave the second process microchannels, the combined internal volume of the second header and the second footer being up to about 40% of the internal volume of the second process microchannels; the fourth fluid mixture being maintained in the second microchannel separator until at least part of the second fluid component is sorbed by the second sorption medium; purging the second microchannel separator to displace non-sorbed parts of the fourth fluid mixture from the second microchannel separator; and
(IV)(B) desorbing the second fluid component from the second sorption medium and flowing a second flush fluid through the second microchannel separator to displace the desorbed second fluid component from the second microchannel separator.
In one embodiment, the invention relates to a process for separating a fluid component from a fluid mixture comprising the fluid component, the process comprising:
(I)(A) flowing the fluid mixture into a first microchannel separator; the first microchannel separator comprising a plurality of first process microchannels containing a first sorption medium, a first header providing a flow passageway for fluid to enter the first process microchannels, and a first footer providing a flow passageway for fluid to leave the first process microchannels, the combined internal volume of the first header and the first footer being up to about 40% of the internal volume of the first process microchannels; the fluid mixture being maintained in the first microchannel separator until at least part of the fluid component is sorbed by the first sorption medium; removing non-sorbed parts of the fluid mixture from the first microchannel separator;
(I)(B) desorbing the fluid component from the first sorption medium and flowing a first flush fluid through the first microchannel separator to displace the desorbed fluid component from the first microchannel separator;
(II)(A) flowing the non-sorbed part of the fluid mixture removed from the first microchannel separator during step (I)(A) into a second microchannel separator; the second microchannel separator comprising a plurality of second process microchannels containing a second sorption medium, a second header providing a flow passageway for fluid to enter the second process microchannels, and a second footer providing a flow passageway for fluid to leave the second process microchannels, the combined internal volume of the second header and the second footer being up to about 40% of the internal volume of the second process microchannels; the non-sorbed part of the fluid mixture being maintained in the second microchannel separator until at least part of the fluid component is sorbed by the second sorption medium; purging the second microchannel separator to displace non-sorbed parts of the fluid mixture from the second microchannel separator; and
(II)(B) desorbing the fluid component from the second sorption medium and flowing a second flush fluid through the second microchannel separator to displace the desorbed fluid component from the second microchannel separator.
The temperature of the sorption medium and/or the pressure within the process microchannels may be changed as the inventive process progresses from step (A) to step (B). In one embodiment, the sorption medium is at a lower temperature during step (A) as compared to the temperature used during step (B). In this embodiment, the process may be referred to as temperature swing sorption (TSS) or temperature swing adsorption (TSA) process.
In one embodiment, the inlet and outlet channels of the microprocess separator may be the same lines, i.e., the fluids can be introduced into the microchannel separator and removed from the microchannel separator via the same ports to the microchannel separator, thereby minimizing the number of entries that need to be fabricated into the microchannel separator.